Man-made carbon dioxide emissions are polluting our oceans, threatening the marine animals that live there

Four years ago wild-oyster fishermen in Washington State began to notice something rather strange going on. In the brackish waters of Willapa Bay, where cold, nutrient-rich water from the deep ocean wells up and nourishes the oysters and their young, larvae were dying at alarming rates. They simply weren't building shells and growing into adults. Desperate to find answers, the fishermen called the National Oceanic and Atmospheric Administration (NOAA) for help.

A group of NOAA scientists took on the case. Could acidity be to blame? Acid in the ocean is formed when carbon dioxide from the air mixes with saltwater in the sea; when put together, the two undergo a chemical reaction and form carbonic acid. As we pump more carbon dioxide into the air, the result is more carbonic acid in the ocean. And with that increase in acid molecules, the availability of carbonate -- an essential component of shells -- declines. In fact, if acidity gets high enough, shells begin to dissolve. Because of the complexities of ocean science, only recently have we been able to detect these changes in pH, and biologists have only recently begun to grasp just how sensitive organisms are to these fluctuations.

"We look out at the ocean, and it seems fine. It's hard to see what's going on beneath the surface," says NRDC ocean initiative director Sarah Chasis. "But around the world, ocean acidity has increased 30 percent since the time before the industrial revolution."

ACID TEST: The Global Challenge of Ocean Acidification

ACID TEST, a film produced by NRDC, was made to raise awareness about the largely unknown problem of ocean acidification, which poses a fundamental challenge to life in the seas and the health of the entire planet. To see a trailer, watch outtakes, and discover more about this problem visit www.nrdc.org/acidtest .

Climate models predict that, on average, ocean acidity levels will double by the end of the century, threatening not just mollusks and species that build shells but the entire web of ocean life. Plankton, all the way down at the bottom of the food chain, also need to build shells to survive, and as their numbers dwindle, so too will the fish that eat them: haddock, flounder, shrimp, salmon, and pollock, to name a few. We in turn eat those fish, and their value to commercial fisheries is in the billions of dollars a year.

The challenge is to make this invisible crisis visible to the general public and to federal policy makers. In August, NRDC released Acid Test, a documentary film narrated by Sigourney Weaver and distributed by the Discovery Channel's Planet Green.

Acid Test delivered a blunt message to a national TV audience: if we do nothing to reverse the acidification process, coral reefs could vanish within 30 years, jeopardizing hundreds of thousands of marine species they support. If ocean acidity continues to increase, we'll see a lot worse than baby mollusks not being able to build shells.

NRDC hopes growing awareness on Capitol Hill of ocean acidification will play a role in ensuring that the American Clean Energy and Security Act includes provisions that would specifically regulate CO2 emissions (in addition to other greenhouse gas emissions that contribute to global warming but do not contribute to ocean acidification). We also need to move forward in developing a national ocean policy that would reestablish ocean health by reducing overfishing and creating marine protected areas -- essentially, national parks for the sea. Such protection is critical: just as the human body is more susceptible to infection when it is exhausted and malnourished, the ocean is more vulnerable to the effects of acidification and warmer temperatures when its overall health is compromised.

"If the ocean is healthy, it can better handle the impact of carbon pollution," says Lisa Suatoni, a biologist with NRDC's ocean initative (see "Whatever It Takes," this issue). "Areas set aside as preserves can nurture source populations of marine species for the rest of the ocean, helping it weather the storms of change."

This summer ushered in a welcome sign of progress. In June, President Barack Obama announced the formation of an Ocean Policy Task Force (see "The Law of the Sea," this issue) charged with creating comprehensive ocean protection policies -- a sort of Clean Air Act for the seas. The United States controls more ocean area than any other country in the world, but in a rather scattered fashion: some 140 different laws and 20 different federal agencies regulate its use. Chasis and Suatoni are pleased that the federal government has begun to take steps toward establishing a single set of ocean rules. "Seventy-one percent of the planet's surface is covered by the ocean," Chasis says. "We often forget this, so we forget to protect it." Soon, she hopes, the old maxim "out of sight, out of mind" will no longer apply to our seas.

Molly Webster is the assistant editor at OnEarth magazine. She is also the science producer for The Takeaway, a radio production from Public Radio International, the New York Times, and the BBC that's causing a radio revolution. Works appear in Scien... READ MORE >

OnEarth is published by the Natural Resources Defense Council. The opinions expressed by its editors and writers are their own and do not necessarily reflect the policies or positions of NRDC. Learn more.